Reducing protein fouling on biomaterials is desired in a number of applications. For example, deposition of proteinaceous tear film components onto contact lens materials has been suggested to result in reduced visual performance [1], comfort [2,3], and in-eye wettability [4], as well as to produce inflammatory complications [5,6,7]. End of day dryness, potentially the result of the presence of a protein layer, has been reported as being experienced by between 25% and 30% of soft contact lens wearers [8], with 35% of patients permanently ceasing use of contact lenses due to complications associated with discomfort and dryness [9].
To alleviate these problems, lens companies have developed novel lens materials. One such material, recently introduced by CIBA Vision contains an internal wetting agent which is reported to be released throughout the day, providing a wetted layer. Another material, introduced by Johnson and Johnson Vision Care in Europe is reported to contain an internal wetting agent which is not released but which migrates to the surface of the material, again providing a continuously wetted surface that presumably has decreased protein adsorption.
Materials with a wetting agent have also been suggested to exhibit increased lubricity and have lower coefficients of friction than their unmodified counterparts. Lubricity is not only important for lens materials, but also in materials having other applications. For example, pacemaker leads must be coated with an insulating material, usually a silicone based polymer, for obvious reasons. However, when these materials are inserted, low surface friction between the material and the surrounding biological environment is critical. Similarly, intraocular lenses must pass through a small bore injector and therefore must have lubricious surfaces to minimize the potential for surgeon error on implantation.
It is desirable, thus, to develop a biomaterial having properties which alleviate at least one of the disadvantages of prior polymer-based biomaterials.